Add lifetime parameters to Parsed and Resolved

Future-proofing

5 files changed, 52 insertions, 23 deletions

diff --git a/dhall/src/expr.rs b/dhall/src/expr.rs
index 1ce20e3..e3a2fe5 100644
--- a/dhall/src/expr.rs
+++ b/dhall/src/expr.rs
@@ -1,5 +1,6 @@
 use crate::imports::ImportRoot;
 use dhall_core::*;
+use std::marker::PhantomData;
 
 macro_rules! derive_other_traits {
     ($ty:ident) => {
@@ -20,13 +21,39 @@ macro_rules! derive_other_traits {
     };
 }
 
+macro_rules! derive_other_traits_ {
+    ($ty:ident) => {
+        impl<'a> std::cmp::PartialEq for $ty<'a> {
+            fn eq(&self, other: &Self) -> bool {
+                self.0 == other.0
+            }
+        }
+
+        impl<'a> std::fmt::Display for $ty<'a> {
+            fn fmt(
+                &self,
+                f: &mut std::fmt::Formatter,
+            ) -> Result<(), std::fmt::Error> {
+                self.0.fmt(f)
+            }
+        }
+    };
+}
+
 #[derive(Debug, Clone, Eq)]
-pub struct Parsed(pub(crate) SubExpr<X, Import>, pub(crate) ImportRoot);
-derive_other_traits!(Parsed);
+pub struct Parsed<'a>(
+    pub(crate) SubExpr<X, Import>,
+    pub(crate) ImportRoot,
+    pub(crate) PhantomData<&'a ()>,
+);
+derive_other_traits_!(Parsed);
 
 #[derive(Debug, Clone, Eq)]
-pub struct Resolved(pub(crate) SubExpr<X, Normalized>);
-derive_other_traits!(Resolved);
+pub struct Resolved<'a>(
+    pub(crate) SubExpr<X, Normalized>,
+    pub(crate) PhantomData<&'a ()>,
+);
+derive_other_traits_!(Resolved);
 
 #[derive(Debug, Clone, Eq)]
 pub struct Typed(pub(crate) SubExpr<X, Normalized>, pub(crate) Option<Type>);
diff --git a/dhall/src/imports.rs b/dhall/src/imports.rs
index b5546b2..6b6e2e7 100644
--- a/dhall/src/imports.rs
+++ b/dhall/src/imports.rs
@@ -3,6 +3,7 @@ use crate::expr::*;
 use dhall_core::*;
 use std::fs::File;
 use std::io::Read;
+use std::marker::PhantomData;
 use std::path::Path;
 use std::path::PathBuf;
 
@@ -48,10 +49,10 @@ fn load_import(f: &Path) -> Result<Normalized, Error> {
     Ok(Parsed::parse_file(f)?.resolve()?.typecheck()?.normalize())
 }
 
-fn resolve_expr(
-    Parsed(expr, root): Parsed,
+fn resolve_expr<'a>(
+    Parsed(expr, root, marker): Parsed<'a>,
     allow_imports: bool,
-) -> Result<Resolved, ImportError> {
+) -> Result<Resolved<'a>, ImportError> {
     let resolve = |import: &Import| -> Result<Normalized, ImportError> {
         if allow_imports {
             let expr = resolve_import(import, &root)?;
@@ -61,36 +62,36 @@ fn resolve_expr(
         }
     };
     let expr = expr.as_ref().traverse_embed(&resolve)?;
-    Ok(Resolved(rc(expr)))
+    Ok(Resolved(rc(expr), marker))
 }
 
-impl Parsed {
-    pub fn parse_file(f: &Path) -> Result<Parsed, Error> {
+impl<'a> Parsed<'a> {
+    pub fn parse_file(f: &Path) -> Result<Parsed<'a>, Error> {
         let mut buffer = String::new();
         File::open(f)?.read_to_string(&mut buffer)?;
         let expr = parse_expr(&*buffer)?;
         let root = ImportRoot::LocalDir(f.parent().unwrap().to_owned());
-        Ok(Parsed(expr, root))
+        Ok(Parsed(expr, root, PhantomData))
     }
 
-    pub fn parse_str(s: &str) -> Result<Parsed, Error> {
+    pub fn parse_str(s: &'a str) -> Result<Parsed<'a>, Error> {
         let expr = parse_expr(s)?;
         let root = ImportRoot::LocalDir(std::env::current_dir()?);
-        Ok(Parsed(expr, root))
+        Ok(Parsed(expr, root, PhantomData))
     }
 
-    pub fn parse_binary_file(f: &Path) -> Result<Parsed, Error> {
+    pub fn parse_binary_file(f: &Path) -> Result<Parsed<'a>, Error> {
         let mut buffer = Vec::new();
         File::open(f)?.read_to_end(&mut buffer)?;
         let expr = crate::binary::decode(&buffer)?;
         let root = ImportRoot::LocalDir(f.parent().unwrap().to_owned());
-        Ok(Parsed(expr, root))
+        Ok(Parsed(expr, root, PhantomData))
     }
 
-    pub fn resolve(self) -> Result<Resolved, ImportError> {
+    pub fn resolve(self) -> Result<Resolved<'a>, ImportError> {
         crate::imports::resolve_expr(self, true)
     }
-    pub fn skip_resolve(self) -> Result<Resolved, ImportError> {
+    pub fn skip_resolve(self) -> Result<Resolved<'a>, ImportError> {
         crate::imports::resolve_expr(self, false)
     }
 }
diff --git a/dhall/src/tests.rs b/dhall/src/tests.rs
index 798f3e9..14c2a5f 100644
--- a/dhall/src/tests.rs
+++ b/dhall/src/tests.rs
@@ -99,7 +99,8 @@ pub fn run_test(
                 assert_eq_pretty!(expr, expected);
 
                 // Round-trip pretty-printer
-                let expr: Parsed = crate::from_str(&expr.to_string(), None)?;
+                let expr_string = expr.to_string();
+                let expr: Parsed = crate::from_str(&expr_string, None)?;
                 assert_eq!(expr, expected);
 
                 return Ok(());
diff --git a/dhall/src/traits/deserialize.rs b/dhall/src/traits/deserialize.rs
index 1fbdfe1..3e8cc5e 100644
--- a/dhall/src/traits/deserialize.rs
+++ b/dhall/src/traits/deserialize.rs
@@ -5,18 +5,18 @@ pub trait Deserialize<'a>: Sized {
     fn from_str(s: &'a str, ty: Option<&Type>) -> Result<Self>;
 }
 
-impl<'a> Deserialize<'a> for Parsed {
+impl<'de: 'a, 'a> Deserialize<'de> for Parsed<'a> {
     /// Simply parses the provided string. Ignores the
     /// provided type.
-    fn from_str(s: &'a str, _: Option<&Type>) -> Result<Self> {
+    fn from_str(s: &'de str, _: Option<&Type>) -> Result<Self> {
         Ok(Parsed::parse_str(s)?)
     }
 }
 
-impl<'a> Deserialize<'a> for Resolved {
+impl<'de: 'a, 'a> Deserialize<'de> for Resolved<'a> {
     /// Parses and resolves the provided string. Ignores the
     /// provided type.
-    fn from_str(s: &'a str, ty: Option<&Type>) -> Result<Self> {
+    fn from_str(s: &'de str, ty: Option<&Type>) -> Result<Self> {
         Ok(Parsed::from_str(s, ty)?.resolve()?)
     }
 }
diff --git a/dhall/src/typecheck.rs b/dhall/src/typecheck.rs
index 4881972..41c1b69 100644
--- a/dhall/src/typecheck.rs
+++ b/dhall/src/typecheck.rs
@@ -11,7 +11,7 @@ use dhall_generator as dhall;
 
 use self::TypeMessage::*;
 
-impl Resolved {
+impl<'a> Resolved<'a> {
     pub fn typecheck(self) -> Result<Typed, TypeError> {
         type_of(self.0.clone())
     }